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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

39301 results found.

  1. Fermi Gamma-ray Burst Monitor trigger 788833547/251231018 is not a GRB
  2. GRB 251230A: Swift-XRT refined Analysis
  3. GRB 251231A: Fermi GBM Final Real-time Localization
  4. GRB 251222A: Mondy Optical Observations
  5. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  6. GRB 251230A: Swift/UVOT detection
  7. GRB251230A: 7DT optical upper limits
  8. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  9. GRB 251230A: GOTO optical upper limit
  10. GRB 251230A / EP251230a: SVOM/VT optical observation
  11. GRB 251230A: Enhanced Swift-XRT position
  12. GRB 251230A: Early optical counterpart detection by LCO.
  13. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  14. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  15. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  16. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  17. Swift GRB 251230A: Global MASTER-Net observations report
  18. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  19. EP251229a: Global MASTER-Net observations report
  20. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  21. GRB 251226A: Glowbug gamma-ray detection
  22. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  23. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  24. Fermi GRB 251228A: Global MASTER-Net observations report
  25. GRB 251228A: Fermi GBM Final Real-time Localization
  26. GRB 251226A: SVOM/GRM observation
  27. GRB 251226A: GECAM-B detection
  28. SVOM GRB251227.07: Global MASTER-Net observations report
  29. IceCube Alert 251225.84: Global MASTER-Net observations report
  30. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  31. Fermi Gamma-ray Burst Monitor trigger 788368008/251225630 is not a GRB
  32. GRB 251222A: NUTTelA-TAO Early Measurements
  33. GRB 251222A/EP251222b: Optical detection with Kinder observations
  34. GRB 251221A: Swift-BAT refined analysis
  35. GRB 251222A/EP251222b: FTW optical and NIR observations
  36. GRB 251205A: Kilonova-Catcher optical afterglow detection
  37. GRB 251222A: AbAO optical observations
  38. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  39. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  40. GRB 251222A: ZTSH BVRI optical observations
  41. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  42. GRB 251222A: Continued 1.3m DFOT optical observation
  43. EP251220a: 3.6m DOT optical afterglow detection
  44. GRB 251222A: Fermi GBM Observation
  45. EP251220a: CrAO ZTSh optical observations
  46. EP251221a: PRIME upper limit
  47. EP251222a: Global MASTER-Net observations report
  48. GRB 251222A / EP251222b: GECAM-B observation
  49. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  50. Konus-Wind detection of GRB 251222A / EP251222b
  51. GRB 251222A: Swift-XRT afterglow detection
  52. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  53. GRB 251222A / EP251222b: GOTO optical counterpart detection
  54. GRB 251222A / EP251222b: LCO optical observations
  55. GRB 251222A: 1.3m DFOT optical detection
  56. GRB251221A: 7DT optical upper limits
  57. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  58. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  59. EP251222b/GRB 251222A: SVOM/GRM observation
  60. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  61. EP251221a: Global MASTER-Net observations report
  62. GRB 251222A: PRIME near-infrared detection
  63. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  64. GRB 251222A: NOT optical observations
  65. IPN triangulation of GRB 251220B (short)
  66. GRB 251222A: Swift ToO observations
  67. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  68. GRB 251222A: SVOM/VT optical candidate
  69. GRB 251222A: SVOM detection of a long burst
  70. SVOM GRB251222A: Global MASTER-Net observations report
  71. GRB 251222A: Fermi GBM Final Real-time Localization
  72. EP251220a: PRIME upper limit
  73. GRB 251221A: PRIME near-infrared observation
  74. GRB 251221A: UAFO and Mondy optical upper limit
  75. GRB 251221A: Swift-XRT refined Analysis
  76. GRB 251221A: Swift/UVOT Upper Limits
  77. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  78. GRB 251221A: Enhanced Swift-XRT position
  79. GRB 251221A: Fermi GBM Observation
  80. GRB 251221B: Fermi GBM Final Real-time Localization
  81. GRB 251220B: SVOM/GRM observation of a short burst
  82. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  83. GRB 251221A: COLIBRÍ detection of the optical counterpart
  84. EP 251220a: COLIBRÍ detection of the optical counterpart
  85. GRB 251221A: Swift detection of a burst
  86. Swift GRB251221A: Global MASTER-Net observations report
  87. GRB 251221A: Fermi GBM Final Real-time Localization
  88. EP251220a: Global MASTER-Net observations report
  89. SVOM GRB251220.98: Global MASTER-Net observations report
  90. GRB 251220B: Fermi GBM Final Real-time Localization
  91. GRB 251219A: SVOM/GRM observation of a short burst
  92. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  93. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  94. GRB 251220A: MAXI/GSC detection
  95. GRB 251215A: Swift-XRT afterglow detection
  96. IceCube-251218A: COLIBRÍ optical upper limits
  97. SVOM GRB251219.11: Global MASTER-Net observations report
  98. IceCube Alert 251218.85: Global MASTER-Net observations report
  99. GRB 251214B: VIRT Optical Upper Limit
  100. Fermi trigger No 787736968: Global MASTER-Net observations report

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